Conventional part retainers for retaining and loading a collection of a large number of parts in a part supply apparatus include retaining tapes with a large number of housing recesses formed at a specified interval. After housing parts in the housing recesses, such part retainers cover the top surface thereof with cover tapes to prevent the parts from falling out.
Such part retainers, however, require parts to be covered with cover tapes during housing and the tapes to be released and wound during part supply, thereby requiring a part supply apparatus of a complicated configuration. In addition, the release tapes must be used, thereby increasing costs.
As a device that solves this problem, the applicant proposed in JPA 6-156562, a part retainer 31 comprising a connected retaining units 32 each having a housing recess 33 in which a part is housed and an engaging piece 34 disposed in the opening for preventing the part from falling out, as shown in FIG. 13. The engaging piece 34 has a protrusion 36 protruding therefrom, is disposed at the end of a supporting piece 35 integrally extending from the sidewall of the retaining unit 32, and protrudes into the opening of the housing recess 33. Since the protrusion 36 on the top surface of the engaging piece 34 engages a guide groove (not shown) formed in a guide rail through which the part retainer 31 travels, the engaging piece 34 is guided by the guide groove to move toward a withdrawing position as the part retainer 31 moves, thereby enabling the part to be housed in and removed from the housing recess 33. Reference numeral 37 designates a feed hole formed in either side of the retaining unit 32, and 38 is a connecting piece for connecting retaining units 32 together.
In the part retainer disclosed in the above publication, however, if the engaging piece 34 remains at the withdrawing position for a long time, a creep phenomenon may cause the supporting piece 35 to remain deformed and to be prevented from elastic return. Thus, the engaging piece 34 cannot reliably retain parts.
In addition, since the engaging piece 34 protrudes into the housing recess 33, a notch opposite to the engaging piece 34 must be formed during molding of the retaining unit 32, and the part cannot be engaged or retained in its full circumference. Consequently, some parts cannot be stably retained.
Furthermore, conventional part supply apparatuses for supplying parts to an electronic part mounting machine have a structure in which the travelling surface for the part retainer is completely covered near a part removal position, as shown in FIG. 25. Thus, if in particular, due to the switching of product types, the part retainer is removed from the part supply apparatus before all the housed parts have been used up, the tape must be cut before or after the part removal section and rewound to a feed or winding reel. If parts are used again, the tape must be connected again, and a large amount of time is required to replace the tape.